Method of manufacturing shielding conduit assemblies



Nov. 3, 1942. T. w. MILTON 2,300,517

METHOD OF MANUFACTURING SHIELDING CODUIT ASSEM'BLIES y Filed April e,1942 l {LLI-Sigi;

Patented Nov. 3, 1942 A 2,300,511., i' l UNITED STATES PATENT OFFICER lMETHOD crsmnlud Thomas W. Milton, Detroit, Mich., assignornto TheFlex-O-Tube Company, a. corporation of Delaware Application April 6,1942, SeriaiNm 437,747 2 Claims. (Cl. 1548) This invention relates tothe method of m-anu- Referring now to the drawing wherein-like 1faoturing shielding conduit assemblies and in numerals refer to like andcorresponding parts particular to the method of assembling couplingthroughout the several views, the illustrative emmembers on fiber glassand wire bra-id type nexbodiment of the invention disclosed is shown inible shielding condui 6 conjunction with a coup member I0 and a Thedevelopment of shielding conduit composed flexible shielding conduit II.

of a wire braid disposed between a plurality of pling member showncomprises an outer shell and electrically connecting coupling members to10 -At the annular base |00 of .the said coupling memeach layer oflacquer coated'iiber glass fabric is a sleeve I5 extends. An 'innercircumferential free to move with respect to adjacent layers and grooveI=6 is Iprovided in the base |00 of the couthe wire braid,.a sure andpermanent means of pling member I to accommodate a charge of uniformlyanchoring rthe conduit in the coupling l solder I'I as indicated inFigs. 2 and `3 by means mem-ber and positively grounding the wire braidof which a nut retainingsleeve I8 having a radi-- of the conduit to thecoupling member is necesally extending collar I9 ispermanently brazed tosary to prevent the conduit from pulling out the the coupling member I0.The base I 00 of the iltting. said coupling member I0 is counterboreda-t IIII To accomplish the foregoing, the method of 2o to accommodatethe said nut retaining sleeve I8 manufacturing shielding conduitassemblies so as to provide a full diameter inner passage suits in thatthe shielding conduit becomes fixed the fitting I0 is retainedethereonby means of the coupling member .by providing a uniform comsleeve I8being telescoped through the said nut. bined electrical and structuralannular bond be- 20 as indicated in Figs. 2 and 3 prior to assemblingtween the outer shell of the coupling member 'and brazing the nutretainer sleeve I-8 into the and the woven wire braid shield whichprevents end of the base of the said coupling member I 0.

' eccentric creeping of the woven wire shield with- Although a swivelnut 20 is shown on the coupling in the conduit near the end thereof../By unimember I0, it is obvious that a iixed nut or a iormly anchoringthe woven wire-shield annularly male threaded end may be formed on thebase of around the inner periphery of the coupling memthe said -tting I0the instant invention relatow of the brazing or soldering materials andthe 4C I2 thereof without damage to the ber glasscome apparent byreference to the following dea heat resistant lacquer, a layer of wovenwire' accompanying drawing,inwhich: forcement, and one or more outercomposite Fig.' 1 is an enlarged longitudinal view, part in layers 22each composed oi wire glass fabric coated section and part in elevation,showing a shielding with a heat resistant lacquer. The said iiexibleconduit having a coupling member uniformly U0 shielding conduit II ischaracterized by each commechanically anchored thereon and electricallyposite layer 22 being slidable during ilexing on connected thereto inaccordance with this inventhe composite layer 22 .therebelow or on thewoven tion.

Fig. 2 is an enlarged sectional view showing the conduit shown comprisestwo inner composite method of preparing the 'coupling member and 5- onewoven wire shielding layer 2'3, and conduit for crimping and brazing.two outer composite layers 22.

Fig. 3 is an enlarged sectional view similar to To prepare the saidilexible shielding conduit Fig. 2 showing the iltting and couplingmember I I for mechanical and electrical union with the I crimped readyfor brazing and a preferred applicoupling member I0. the two outercomposite cation ofbrazing heat thereto. layers 22 of wire glass fabriccoated with heat resistant lacquer are stripped back a short distancefrom the end of the said conduit II, a solder flux is applied to theexposed woven wire braid 23, the exposed woven wire braid 23 is thenwrapped with a plurality of layers 24 of fiuxed solder foil, and thestripped and wrapped end of the said flexible conduit II is telescopedin the end of the coupling member l between the outer shell I2 andtubular stem I3 thereof as illustrated in Fig. 2; the lower .portion ofthe inner and outer walls of the outer shell I2 and inner tubular stemIJ having been previously fluxed.

A'Ihe coupling member I0 is then crimped as vindicated in Fig. 3 with aplurality of shallow crimps 25 and one deep crimp 26, the said deepcrimp F26 being disposed over the said fluxed solder foil 24 andlongitudinally inward of the endsthereof.

The coupling member I0 with the flexible conduit II therein is thenpositioned over a suitable jig 21 held on a table 28 and heat is appliedas indicated by the arrows A in Fig. 3 to the coupling; member I0suilicient to braze the woven wire braid 23 to the coupling member I0uniformly around the inner peripheryof the outer shell I2 at the deepcrimp 26 therein as indicated lby the numerals 29 and 30 in Fig. 1.

' A heat shield 3| is preferably employed if the brazing heat A isapplied by means other than electrically to localize the brazing heat Awhereby to prevent unnecessary melting of the lacquer coating of thecomposite layers 22 of the flexible shielding conduit II. y

If the coupling member I0 is of the type shown, the heat application Bmay become unnecessary to melt the solder I1 to braze the sleeve I8 andcollar I9 to the coupling member I0. The heat application at B,if'employed, is preferably simultaneous with the heat application A andis only employed to accomplish the melting of the charge of solder I1and the brazing at 32 which is not a part or element of the instantinvention.

The important item of the method of positively anchoring the iiexibleshielding conduit I I in-the coupling member I0 is that the iluxedsolder foil l wrapping the exposed woven wire shield with a 24 iscrimped and held in place by the crimping 23 oi the outer shell I2 andis held under crimped pressure during brazing which causes the solder orbrazing material 24 to enter the interstices of the woven wire braid 23of the shielding conduit II as indicated by the numeral 29 in Fig. 1,the surplus flowing to .points indicated by the numeral 30 in Fig. 1.This positiveuniform anchoring of the woven wire braid 23 atA 29 asindicated it Fig. 1 assures complete anchorage entirely and uniformlyaround the fitting thereby preventing uneven stretching of the wovenwire braid 22 with respect to the composite-'layers 22 of the flexibleshielding conduit II during ilexing which prevents the breaking oropening of the shieldv 23 at or near the coupling member Ill which isdeleterious to shielding effect and causes mechanical weakening of theflexible shielding conduit II.

The particular method of accomplishing the connection of the flexibleshielding conduit II to the coupling member I0 herein disclosed has beenfound to assure the uniform, complete and positive structural anchorageand electrical bonding of liber glass-woven wire type flexible conduitII to the coupling member I0.

Although but a single illustrative method has been herein disclosed indetail, it is obvious that the advantageous method of anchoring andconnecting flexible shielding conduits to coupling members may bealtered to accommodate it to other like and similar types of flexibleshielding conduits and coupling members than the ones herein disclosedfor purposes of illustrating the invention.

I claim:

l. The method of manufacturing shielding conduit assemblies of the typewherein a ilexible shielding conduit composed of a plurality ofinsulating layers and a woven wire shield disposed between two of saidAinsulating layers is provided with a coupling member including a shelland a concentric stem therewithin, comprising removing the outerinsulating `layers suiiiciently to expose said woven wire shield of saidshielding conduit a distance from the end of said shielding conduit lessthan the depth of the coupling shell,

plurality of layers of rluxed solder foil, telescope ing the solder foilwrapped end ofl said shielding conduit within the said coupling shelland over the Isaid stem therewithin, crimping the said shell oppositethe solder foil wrapped woven wire.

shield to create initial circumferential pressure annularly on saidsolder foil wrapped woven wire shield, and applying sufiicient heat tosaid shell opposite said solder foil wrapping therewithin to braze saidwoven wire shield to said shell while said solder foil is under saidannular initial circumierential pressure whereupon a uniform annularanchorage of said shielding conduit within said coupling member isaccomplished simultaneously with embedding solder adhering to saidcoupling shell in said woven wire shield.

2. The method of manufacturing shielding conduit assemblies of the typewherein a. flexible shielding conduit composed of a plurality ofinsulating layers and a woven wire shield disposed between two of saidinsulating layers is provided with a coupling member including a shellanda concentric stern therewithin, comprising removing the outerinsulating layers sufliciently to expose said woven wire shield of saidshielding conduit a. distance from the end of said shielding conduitless than the depth of the coupling shell, wrapping the exposed wovenwire shield with a plurality of layers of iluxed solder foil,telescoping the solder foil wrapped end of said shielding conduit withinthe said coupling shell and over the said stem therewithin, crimping thesaid shell outwardly of and opposite the solder foil wrapped woven wireshield to create initial circumferential pressure annularly on saidshielding conduit and on the solder foil wrapped woven wire shield, andapplying suilicient heat to said shell opposite said solder foilwrapping there-

